1. Field of the Invention
The present invention relates to a V-type engine.
2. Description of the Related Art
US 2014/0322997 A1 discloses an outboard motor powered by a V-type engine. This outboard motor is equipped with an in-bank exhaust system that discharges exhaust gases to the inside of two cylinder banks. In the V-type engine, a floating structure is used to absorb dimensional errors of the respective components.
In detail, an exhaust pipe includes two upstream end portions connected to two exhaust manifolds, respectively. One upstream end portion is connected to one exhaust manifold via two O-rings, and is movable with respect to the one exhaust manifold. The other upstream end portion is fixed to the other exhaust manifold, and is not movable with respect to the other exhaust manifold.
One upstream end portion of the exhaust pipe is inserted into an insertion hole provided in the one exhaust manifold. The space between an outer peripheral surface of the upstream end portion and an inner peripheral surface of the insertion hole is sealed by two O-rings. The O-rings are held in annular grooves provided in the insertion hole. One upstream end portion of the exhaust pipe is movable with respect to the one exhaust manifold in a state where the space between the upstream end portion and the insertion hole is sealed by the two O-rings. The position of the exhaust pipe with respect to the one exhaust manifold changes according to a cumulative value of dimensional errors.
In the V-type engine described in US 2014/0322997 A1, by using a floating structure, both a desired sealing performance and absorption of dimensional errors are achieved. However, since O-rings are used to seal the connecting portion between the exhaust pipe and the exhaust manifold, the exhaust manifold is required to include the insertion hole into which the upstream end portion of the exhaust pipe is inserted. Further, two annular grooves that hold the two O-rings must be provided on the inner peripheral surface of the insertion hole. Therefore, the structure of the connecting portion becomes complicated.